A person who serves in a supporting, secondary, or subsidiary capacity; an assistant.
A comedian who plays a secondary or supporting role, especially as straight man and traditionally in vaudeville or burlesque theatre.
One who serves in a subordinate or menial role.
A person in a play or movie with a minimal part; an extra.
One who plays a leading or substantial role as a supporter, proponent, etc. representing a group, cause, or point of view.